Hello, I am using a 36D DC Planetary Gearmotor w/ Encoder - 24V 230RPM purchased from RobotShop.
Issue: When motor spins, channel A remains flat at ~250–500 mV and there is no change in A waveform when rotating shaft (slow or fast).
Things that work:
Channel B shows a clean square wave
I have the motor terminals hooked up to a DC power supply, and encoder Vcc and Gnd are hooked up to the same DC power supply. An oscilloscope is measuring the A and B waveforms.
It sounds like you have a dead output on Phase A, likely due to a faulty Hall Effect sensor or a missing pull-up resistor. Since these encoders often have open-collector outputs, Channel A will stay “low” unless you provide a path to Vcc.
Try connecting a 10kΩ resistor between the Signal A wire and your encoder power supply. If adding the resistor doesn’t produce a square wave while the motor spins, the internal sensor on the motor’s PCB is likely defective and the unit may need to be replaced.
You may also want to contact manufacturer directly for troubleshooting and support, and you can do it via RobotShop platform:
Click on the Ask the vendor button and send them a message:
